Depends on the depth. “Pizza box” generally referred to the smaller rack mounted stuff that could fit in the 24 inch depth racks. They were called pizza boxes because 19 inch width and that depth made them nearly square.
A typical 1U full sized server is 40+ inches though. Those are really annoying to put at a desk.
Not sure what you mean, but nobody I know of referred to the 4ft long servers as pizza boxes. Because the name sort of implied it was something small enough to throw on a desk and stack stuff on.
